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Why Classify Streams? • Communication Tool • Describe Existing Conditions & Trends • Describe Restoration Goals • Research Tool Stream Classification
| Date post: | 11-Jul-2015 |
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Technology |
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Why Classify Streams?
• Communication Tool
• Describe Existing Conditions & Trends
• Describe Restoration Goals
• Research Tool
Stream Classification
Morphologic Stream Classification Systems
• Schumm (1977)– Alluvial channels
– Meandering, straight, braided
– Type related to channel stability & sediment transport
• Montgomery & Buffington (1993)– Alluvial, colluvial, bedrock channels
– Channel response related to sediment inputs
– 6 classes of alluvial channels: cascade, step-pool, plane-bed, riffle-pool, regime, and braided
• Rosgen (1994)www.wildlandhydrology.com
Rosgen Classification of Natural Rivers
• Based on physical characteristics (empirical)
• Requires field measurements
• Requires bankfull dimensions
www.wildlandhydrology.com
What factors affect stream morphology?
• Width
• Depth
• Slope
• Velocity
• Discharge
• Flow resistance
• Sediment size
• Sediment load
Leopold et al (1964)
Dimension (cross-section)
Pattern (plan form)
Profile (bed form)
Bed material (substrate)
Rosgen Classification of Natural Rivers
Level 1 Rosgen Classification
www.wildlandhydrology.comwww.wildlandhydrology.com
Level 2 Rosgen Classification
www.wildlandhydrology.comwww.wildlandhydrology.com
www.wildlandhydrology.com
www.wildlandhydrology.com
Stream Types in Landscape Positions
A Streams
Incised, Narrow & Deep, Steep Slope
Colluvial Valley
dbkf
Single Thread Channel
ER = Wfpa/Wbkf < 1.4
W/d = Wbkf/dbkf < 12
S > 0.04 ft/ft
A Stream Channel
Bankfull
dmax
Wfpa
Wbkf
A2 Western NC
Aa+ Streams
Very Steep
(>0.1 ft/ft)
A1a+ Western NC
B Streams
Moderately Incised, Wide & Shallow,
Moderate Slope, Colluvial Valley
dbkf
Single Thread Channel
ER = Wfpa/Wbkf = 1.4 – 2.2
W/d = Wbkf/dbkf > 12
S = 0.02 – 0.04 ft/ft
B Stream Channel
Bankfull
dmax
Wfpa
Wbkf
www.wildlandhydrology.com
B3 Western NC
C Streams
Not Incised, Wide & Shallow, Low Slope
Alluvial Valley
dbkf
Single Thread Channel
ER = Wfpa/Wbkf > 2.2
W/d = Wbkf/dbkf > 12
S < 0.02 ft/ft
C Stream Channel
Bankfull
dmax
Wfpa
Wbkf
www.wildlandhydrology.com
C4 New Zealand
C4 Utah
E Streams
Not Incised, Narrow & Deep, Low Slope
Alluvial Valley
dbkf
Single Thread Channel
ER = Wfpa/Wbkf > 2.2
W/d = Wbkf/dbkf < 12
S < 0.02 ft/ft
E Stream Channel
Bankfull
dmax
Wfpa
Wbkf
www.wildlandhydrology.com
E4 Western NC
E4 Central NC
E4b Western NC
E4 Western NC
E4 Western NC
G Streams
Incised
Narrow & Deep
Moderate Slope
dbkf
Single Thread Channel
ER = Wfpa/Wbkf < 1.4
W/d = Wbkf/dbkf < 12
S = 0.02 – 0.04 ft/ft
G Stream Channel
Bankfull
dmax
Wfpa
Wbkf
www.wildlandhydrology.com
G4 Western NC
G4 Eastern NC
G4c Central NC
G5c Alabama
G4
F Streams
Incised, Wide & Shallow, Low Slope
dbkf
Single Thread Channel
ER = Wfpa/Wbkf < 1.4
W/d = Wbkf/dbkf > 12
S < 0.02 ft/ft
F Stream Channel
Bankfull
dmax
Wfpa
Wbkf
www.wildlandhydrology.com
Stream Types in Landscape Positions
www.wildlandhydrology.com
F4 Texas
F4 Alabama
F5 South Carolina
Ugg Texas
D & DA Streams
Multiple Channels, Wide & Shallow, Low Slope
D4 Virginia
dbkf
Multiple Thread Channel
ER = Wfpa/Wbkf > 2.2
W/d = Wbkf/dbkf > 40
D Stream Channel
Bankfull
dmax
Wfpa
Wbkf
www.wildlandhydrology.com
Stream Types in Landscape Positions
www.wildlandhydrology.com
D4 New Zealand
D4 Pennsylvania
C4 -> D4 Western NC
ER=11; W/d=16; S=0.004; D50=1 mm
ER=1.3; W/d=7; S=0.007; D50=1.5 mm
ER=2.2; W/d=14; S=0.024; D50=75 mm
ER=6.5; W/d=10.5; S=0.008; D50=1.5 mm
ER=1.5; W/d=10; S=0.009; D50=2 mm
ER=1.4; W/d=10; S=0.050; D50=50 mm
ER=1.3; W/d=15; S=0.002; D50=0.5 mm
ER=1.3; W/d=7; S=0.007; D50=1.5 mm
ER=5.5; W/d=29; S=0.009; D50=15 mm
ER=2.2; W/d=14; S=0.035; D50=110 mm
ER=5.5; W/d=8.2; S=0.025; D50=12 mm
ER=2.1; W/d=15; S=0.065; D50=120 mm
ER=2.2; W/d=14; S=0.024; D50=75 mm
Stream Channel Succession (WARSSS)
Stream Channel
Succession
(WARSSS)
http://www.epa.gov/WARSSS/
sedsource/successn.htm
Bank Erosion
Monitoring
Harris Reach, South Fork Mitchell River
X-Sec 7+65
0
2
4
6
8
10
0 4 8 12 16 20 24 28 32 36
Distance from Toe Pin (ft)
Ht a
bo
ve T
oe
Pin
(ft)
1/8/97
1/8/97
6/18/97
8/15/97
7/9/98
Bank Erosion Hazard Index (BEHI)
Bank Erosion Hazard Index (BEHI)
Bank Erosion Hazard Index (BEHI)
Why Classify Streams?
• Communication Tool
• Describe Existing Conditions & Trends
• Describe Restoration Goals
• Research Tool
Stream Classification
Morphologic Stream Classification Systems
• Schumm (1977)– Alluvial channels
– Meandering, straight, braided
– Type related to channel stability & sediment transport
• Montgomery & Buffington (1993)– Alluvial, colluvial, bedrock channels
– Channel response related to sediment inputs
– 6 classes of alluvial channels: cascade, step-pool, plane-bed, riffle-pool, regime, and braided
• Rosgen (1994)www.wildlandhydrology.com
Rosgen Classification of Natural Rivers
• Based on physical characteristics (empirical)
• Requires field measurements
• Requires bankfull dimensions
www.wildlandhydrology.com
What factors affect stream morphology?
• Width
• Depth
• Slope
• Velocity
• Discharge
• Flow resistance
• Sediment size
• Sediment load
Leopold et al (1964)
Dimension (cross-section)
Pattern (plan form)
Profile (bed form)
Bed material (substrate)
Rosgen Classification of Natural Rivers
Level 1 Rosgen Classification
www.wildlandhydrology.comwww.wildlandhydrology.com
Level 2 Rosgen Classification
www.wildlandhydrology.comwww.wildlandhydrology.com
Riffle Dimensions
Bankfull
Wbkf
Abkf
Measure Bankfull Width (Wbkf) and Bankfull Area (Abkf)
Mean Depth, dbkf = Abkf / Wbkf
Width to Depth Ratio, W/d = Wbkf / dbkf
dbkf
W/d = 9.3 / 1.5 = 6.2
Entrenchment Ratio
ER = Wfpa / Wbkf
Bankfull
2 x dmax
above thalweg
Wfpa
Wbkf
dmax
Wfpa = Width of Flood Prone Area measured at the
elevation twice bankfull max depth above thalweg
Wbkf = Width of Bankfull Channel
ER = Wfpa / Wbkf = 63 / 15 = 4.2
Bed Material (Substrate)
Silt/Clay: < 0.062 mm
Sand: 0.062 – 2 mm
Gravel: 2 – 64 mm
Cobble: 64 – 256 mm
Boulder: 256 – 2048 mm
Substrate
Characterization
Wolman Pebble Count
www.wildlandhydrology.com
Valley Types: (www.epa.gov/watertrain/stream_class)
Valley Type II
Moderately steep, gentle sloping side
slopes often in colluvial valleys
From EPA Watershed Academy: Fundamentals of the Rosgen Stream Classification System
Valley Types: (www.epa.gov/watertrain/stream_class)
Valley Type VIII
Wide, gentle valley slope with well-developed
floodplain adjacent to river terraces
From EPA Watershed Academy: Fundamentals of the Rosgen Stream Classification System
www.wildlandhydrology.com
Stream Types in Landscape Positions
A Streams
Incised, Narrow & Deep, Steep Slope
Colluvial Valley
www.wildlandhydrology.com
dbkf
Single Thread Channel
ER = Wfpa/Wbkf < 1.4
W/d = Wbkf/dbkf < 12
S > 0.04 ft/ft
A Stream Channel
Bankfull
dmax
Wfpa
Wbkf
A2 Western NC
A2 Montana
A3 Western NC
Aa+ Streams
Very Steep
(>0.1 ft/ft)
A1a+ Western NC
A1a+ Western NC
A1a+ Tennessee
B Streams
Moderately Incised, Wide & Shallow,
Moderate Slope, Colluvial Valley
dbkf
Single Thread Channel
ER = Wfpa/Wbkf = 1.4 – 2.2
W/d = Wbkf/dbkf > 12
S = 0.02 – 0.04 ft/ft
B Stream Channel
Bankfull
dmax
Wfpa
Wbkf
www.wildlandhydrology.com
Stream Types in Landscape Positions
www.wildlandhydrology.com
B3 Western NC
B3 Western NC
B3 Western NC
B4 Tennessee
B3 Western NC
B4 Western NC
B4c Western NC
C Streams
Not Incised, Wide & Shallow, Low Slope
Alluvial Valley
dbkf
Single Thread Channel
ER = Wfpa/Wbkf > 2.2
W/d = Wbkf/dbkf > 12
S < 0.02 ft/ft
C Stream Channel
Bankfull
dmax
Wfpa
Wbkf
www.wildlandhydrology.com
Stream Types in Landscape Positions
www.wildlandhydrology.com
C4 Western NC
C4 Western NC
C4 Washington
C4 New Zealand
C4 Western NC
C5 Alabama
C4 Utah
C4 Western NC
E Streams
Not Incised, Narrow & Deep, Low Slope
Alluvial Valley
dbkf
Single Thread Channel
ER = Wfpa/Wbkf > 2.2
W/d = Wbkf/dbkf < 12
S < 0.02 ft/ft
E Stream Channel
Bankfull
dmax
Wfpa
Wbkf
www.wildlandhydrology.com
Stream Types in Landscape Positions
www.wildlandhydrology.com
E4 Western NC
E4 Central NC
E4 Central NC
E4 Western NC
E4 Western NC
E4b Western NC
E4 Western NC
E5 Central NC
E4 Central NC
E4 Western NC
E4 Western NC
E5 -> G5c AL
G Streams
Incised
Narrow & Deep
Moderate Slope
dbkf
Single Thread Channel
ER = Wfpa/Wbkf < 1.4
W/d = Wbkf/dbkf < 12
S = 0.02 – 0.04 ft/ft
G Stream Channel
Bankfull
dmax
Wfpa
Wbkf
www.wildlandhydrology.com
Stream Types in Landscape Positions
www.wildlandhydrology.com
G4 Western NC
G4 Eastern NC
G5 Headcut
Georgia
G5 Headcut
Georgia
G4c Central NC
G4c Alabama
G4c Alabama
G5c Eastern NC
G5c Alabama
G5c Florida
G4
2003
2000
2003
2001
F Streams
Incised, Wide & Shallow, Low Slope
dbkf
Single Thread Channel
ER = Wfpa/Wbkf < 1.4
W/d = Wbkf/dbkf > 12
S < 0.02 ft/ft
F Stream Channel
Bankfull
dmax
Wfpa
Wbkf
www.wildlandhydrology.com
Stream Types in Landscape Positions
www.wildlandhydrology.com
F1 Asheville
F2 New Zealand
F2 New Zealand
F3 New Zealand
F4 Western NC
F4 Texas
F4 Texas
F4 Alabama
F5 Georgia
F5 South Carolina
Ugg Texas
D & DA Streams
Multiple Channels, Wide & Shallow, Low Slope
D4 Virginia
dbkf
Multiple Thread Channel
ER = Wfpa/Wbkf > 2.2
W/d = Wbkf/dbkf > 40
D Stream Channel
Bankfull
dmax
Wfpa
Wbkf
www.wildlandhydrology.com
Stream Types in Landscape Positions
www.wildlandhydrology.com
D4 Georgia
D4 New Zealand
D4 Oregon
D4 Pennsylvania
C4 -> D4 Western NC
C4 -> D4 Western NC
DA5 Florida
www.wildlandhydrology.com
ER=11; W/d=16; S=0.004; D50=1 mm
ER=1.3; W/d=7; S=0.007; D50=1.5 mm
ER=2.2; W/d=14; S=0.024; D50=75 mm
ER=1.5; W/d=10; S=0.009; D50=2 mm
ER=4.5; W/d=14; S=0.033; D50=75 mm
ER=3.4; W/d=13.2; S=0.012; D50=15 mm
ER=6.5; W/d=10.5; S=0.008; D50=1.5 mm
ER=10; W/d=9.5; S=0.005; D50=0.5 mm
ER=1.5; W/d=10; S=0.009; D50=2 mm
ER=1.4; W/d=10; S=0.050; D50=50 mm
ER=1.3; W/d=15; S=0.002; D50=0.5 mm
ER=1.3; W/d=7; S=0.007; D50=1.5 mm
ER=5.5; W/d=29; S=0.009; D50=15 mm
DA5 FloridaER=18; W/d=45; S=0.0002; D50=0.1 mm
ER=2.2; W/d=14; S=0.035; D50=110 mm
ER=5.5; W/d=8.2; S=0.025; D50=12 mm
ER=2.1; W/d=15; S=0.065; D50=120 mm
ER=2.2; W/d=14; S=0.024; D50=75 mm
